Tool for forming a three dimensional article or container

ABSTRACT

A forming tool assembly and method for forming a cooking element. The forming tool assembly has an upper tool assembly and a lower tool assembly that cooperate to shape the cooking element from an annular cutout.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of PCT Application No.PCT/US2007/081743 filed Oct. 18, 2007, entitled “Tool For Forming AThree Dimensional Article Or Container,” which PCT application claimsthe benefit of U.S. Provisional Application No. 60/829,976 which wasfiled on Oct. 18, 2006, the entire disclosures of both of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to tools and methods for forming materialsinto articles, elements or containers that may be used to hold, contain,or prepare food products or other products.

SUMMARY OF THE INVENTION

In one aspect, the invention is generally directed to a tool for forminga cooking element form a cutout. The tool has a clamping feature thatholds a portion of the cutout in a fixed position during formation ofthe cooking element.

In another aspect, the invention is generally directed to a tool forforming a cooking element from a cutout. The tool comprises a first toolassembly and a second tool assembly. At least one of the first toolassembly and the second tool assembly is moveable between an openposition wherein the cutout is received between the first and the secondtool assembly and a closed position wherein the cutout is formed intothe cooking element. The first and the second tool assembly have acooperating clamping feature that holds a portion of the cutout in afixed position during formation of cooking element.

In another aspect, the invention is generally directed to a method offorming a cooking element. The method comprises providing a tool and acutout to be formed into the cooking element and clamping the cutoutbetween a clamping feature of the tool to hold a portion of the cutoutin a fixed position during formation of the cooking element.

In another aspect, the invention is generally directed to a method offorming a cooking element. The method comprises providing a toolcomprising a first tool assembly and a second tool assembly. The firstand second tool assemblies have a cooperating clamping feature. Themethod further comprises providing a cutout comprising material to beformed into the cooking element and clamping the cutout between theclamping feature of the first tool assembly and the second toolassembly. The method further comprises positioning the first and secondtool assemblies in a closed position to press the cutout between thetool assemblies and form the cutout into the cooking element, whilemaintaining a portion of the cutout in a substantially fixed position.

In another aspect, the invention is generally directed to a method offorming a cooking element. The method comprises providing a toolcomprising a first tool assembly and a second tool assembly and cuttingan annular cutout from a blank. The annular cutout has an outer radialedge, an inner radial edge, and an opening adjacent the inner radialedge. The method further comprises positioning the tool in an openposition wherein the first tool assembly and the second tool assemblyare spaced apart to form a receiving space therebetween, conveying theannular cutout to the tool in the open position and placing the cutoutbetween the first and second tool assembly. The method further comprisesclosing the tool so that the first and second tool assemblies form theannular cutout into a cooking ring.

In another aspect, the invention is generally directed to a cookingelement for heating a food product. The cooking element comprises agenerally annular body comprising a lower edge portion, an upper edgeportion, a curved portion between the lower and upper edge portions, andan annular groove between the upper edge portion and the curved portion.

In another aspect, the invention is generally directed to a cookingelement formed from any of the various methods as shown and/or describedherein.

In another aspect, the invention is generally directed to a cookingelement formed from a forming tool having any of the various featuresshown and/or described herein.

Those skilled in the art will appreciate the above stated advantages andother advantages and benefits of various additional embodiments readingthe following detailed description of the embodiments with reference tothe below-listed drawing figures.

According to common practice, the various features of the drawingsdiscussed below are not necessarily drawn to scale. Dimensions ofvarious features and elements in the drawings may be expanded or reducedto more clearly illustrate the embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of an annular cutout used to form a cookingelement of an exemplary embodiment of the present invention.

FIG. 2 is a bottom plan view of the annular cutout of FIG. 1.

FIG. 3 is a schematic of the cooking element formed from a forming toolof an exemplary embodiment of the present invention.

FIG. 3A is a cross-section including the plane 3A-3A of FIG. 3.

FIG. 4 is a schematic of the cooking element of FIG. 3.

FIG. 5 is a cross-section of the forming tool in a closed position.

FIG. 6 is an enlarged portion of FIG. 5.

FIG. 7 is a perspective of an upper tool assembly of the forming tool.

FIG. 8 is a cross-section of the upper tool assembly.

FIG. 9 is a cross-section of a lower tool assembly of the forming tool.

FIG. 10 is a perspective of the lower tool assembly.

FIG. 11A-11C are enlarged portions of the forming tool showing variousstages of formation of the cooking element from the annular cutout.

Corresponding parts are designated by corresponding reference numbersthroughout the drawings.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The present invention relates generally to various aspects of materials,packages, elements, articles, containers and methods of making suchmaterials, packages, elements, articles and containers. Although severaldifferent inventions, aspects, implementations, and embodiments of thevarious inventions are provided, numerous interrelationships between,combinations thereof, and modifications of the various inventions,aspects, implementations, and embodiments of the inventions arecontemplated hereby. In one illustrated embodiment, the presentinvention relates to forming a heating or cooking element for microwavecooking of food items. However, in other embodiments, the invention canbe used to form articles or containers not used for microwave cooking.

FIG. 3 is a perspective view of a cooking element in the form of acooking ring, generally indicated at 1, used to cook a food product (notshown) such as a frozen pizza. The cooking ring 1 is formed from anannular cutout 5 (FIGS. 1 and 2) that is cut from a paperboard blank(not shown) having at least one layer of microwave interactive material9 (FIG. 2) attached thereto (e.g., covering an entire interior surface29 of the cutout). In accordance with the exemplary embodiment of thepresent invention, the microwave interactive material 9 is, or at leastincludes, a susceptor, although other types and various combinations ofmicrowave interactive elements are also within the scope of the presentinvention, as will be discussed in greater detail below. As will bediscussed below in more detail, the cooking ring 1 is shaped from theannular cutout 5 by a forming tool assembly, generally indicated at 15(FIG. 6).

As shown in FIGS. 1 and 2, the annular cutout 5 has an outer radial edge19 and an inner radial edge 21 defining a center opening 23. The cutout5 has a plurality of radially directed uniformly spaced score lines 27that are typically formed on the interior surface 29 of the cutout in amanner so that the integrity of the microwave interactive material 9 ismaintained or at least substantially maintained. In the illustratedembodiment the score lines 27 extend from the outer radial edge 19 ofthe cutout 5 to a location radially spaced from the inner radial edge ofthe 21. The score lines 27 create weak areas within the paperboard. Theweak areas facilitate the shaping and forming of the annular cutout 5into the cooking ring 1 by a die-forming process using the forming tool15 of the present invention. Nonetheless, the score lines 27 maypossibly be omitted.

As shown in FIGS. 3 and 4, the cooking ring 1 has a generally flat,lower circumferential edge portion 35, a first curved portion 37extending axially upward from the lower circumferential edge portion, asecond curved portion 41 extending axially upward from the first curvedportion, and a generally flat, upper circumferential edge portion 45extending radially inward from the second curved portion. The upper edgeportion 45 has an annular groove 47 (FIG. 3A) adjacent the second curvedportion 41. The cooking ring 1 has an opening 51 defined by an innerradial edge 53 that generally corresponds to the opening 23 of theannular cutout 5. During formation of the cooking ring 1 from theannular cutout 5, the weak areas in the paperboard at the score lines 27of the cutout cause the accumulation of excess paperboard into folds orpleats 49 which are then compressed to strengthen the cooking ring. Thepleats 49 allow portions of the paperboard material to overlap and bendduring the forming process to form the desired cross-sectional shape ofthe cooking ring 1.

FIG. 5 is a sectional view of the forming tool 15 used to form athree-dimensional article or container such as the cooking ring 1. Inthe illustrated embodiment, the tool 15 includes an upper (first) toolassembly 61 and a lower (second) tool assembly 63. The upper and lowertool assemblies 61 and 63 are independently moveable in the verticaldirection Z along a central axis A1 of the assembly to form the annularcutout 5 into the cooking ring 1. It is understood that the upper andlower tool assemblies 61, 63 are moved in the vertical direction Z fromthe position shown in FIG. 5 to form a gap between the assemblies sothat an annular cutout 5 traveling in the horizontal direction X islocated between the upper and lower tool assemblies prior to the formingprocess.

As shown in FIGS. 6 and 8, the upper tool assembly 61 has an nose 67with a flat axial end surface 71 forming a first axial end 73 of theupper tool assembly. As shown in FIG. 7, the axial end 73 includes anannular groove 77 generally adjacent a first curved radial surface 81 ofthe nose 67. In the illustrated embodiment, the annular groove 77 has asquare cross-sectional shape, but it is understood that the groove couldhave other shapes and be otherwise located. The nose 67 has a secondcurved radial surface 85 that is adjacent to an angled conical surface89 of the nose. A cylindrical shaft 93 (FIG. 5) of the nose 67 isreceived in a guide bushing 95 of the upper tool assembly 61. In theillustrated embodiment, the upper tool assembly 61 includes a shim 99 ona flange 103 connected to the cylindrical shaft 93. The shim 99 andflange 103 limit the downward travel of the nose 67 by contact with theaxial end surface 105 of the guide bushing 95. The thickness of the shim99 can be changed to affect the distance of travel of the nose 67.

The upper tool assembly 61 includes a punch 109 having an axial end 111that includes a radially outer, angled surface 115 (FIG. 6) and aradially inner, flat annular surface 119 (FIG. 8). The punch 109 has anaxial opening 123 that receives the guide bushing 95 and cylindricalshaft 93 of the nose 67. The punch 109 has a cylindrical recess 127 inthe flat annular surface 119 that receives a coil spring 131 forapplying a force against the nose 67. During downward travel of uppertool assembly 61, the spring 131 optionally allows the nose 67 to bespaced apart from the punch 109 to accommodate bulging of the annularcutout 5 when the score lines 27 are overlapped to form the cooking ring1. Alternatively, the upper tool assembly 61 can be configured so thatthe nose 67 travels in unison with the punch 90. The nose 67 can befixedly attached to the punch 109 or the nose and the punch can combinedinto a single component for use in forming the cooking element 1 withoutdeparting from the invention. In some embodiments of the invention,additional shims 99 may be added to limit the downward travel of thenose 67 so that the nose and the punch 109 move together (e.g., with theconical surface 89 (FIG. 6) of the nose in contact with the angledsurface 115 of the punch). In some embodiments, operation of the uppertool assembly with the nose 67 and punch 109 moving together in unisonmay be beneficial to reduce wear within the forming tool 15.

The upper tool assembly 61 includes a clamp ring 135 attached to anouter radial surface 139 of the punch 109 by radially directed fasteners(not shown). The clamp ring 135 is attached to a base plate 143 byaxially directed fasteners (not shown). The base plate 143 has an axialopening 145 for receiving the cylindrical shaft 93 of the nose 67 andthe guide bushing 95. Support brackets 153, 155 are attached to theclamp ring 135 on respective opposite sides of the clamp ring. As shownin FIGS. 7 and 8, the upper tool assembly 61 includes an insulator sheet163 attached to the outer axial end surface of the base plate 143. Aheater 167 is connected to the base plate 143 for heating the upper toolassembly 61. The upper tool assembly 61 includes an actuator (e.g., aircylinders, springs, or other actuating device(s) not shown) respectivelyconnected to each of the brackets 153, 155 for activating the clamp ring135.

As shown in FIGS. 5, 9, and 10, the lower tool assembly 63 includes agenerally cylindrical cavity block or cavity 175 having an upper recess179 with a radial shape to correspond with the shape of the cooking ring1. The cavity block 175 has a generally cylindrical lower recess 183(FIG. 9), an upper axial end surface 187, and a lower axial end surface191. The upper recess 179 has an upper curved radial surface 195adjacent the axial end surface 187 of the cavity block 175 andcorresponding with the shape of the first curved portion 37 of thecooking ring 1. A lower curved radial surface 199 extends downward fromthe upper curved surface 195 and corresponds with the shape of thesecond curved portion 41 of the cooking ring 1. The cavity 175 caninclude radially directed vent holes (not shown) passing from an outerradial surface 201 of the cavity to the upper recess 179 to facilitateventing during formation of the cooking ring 1.

A knockout 205 is received in the lower recess 183 of the cavity block175 and has a flat upper axial surface 209 that abuts the lower edge ofthe upper recess 179 at the closed position of the lower tool assembly63 (FIGS. 5 and 9). The knockout 205 includes a generally cylindricalhead 217 having a cylindrical shaft 225 received in a guide bushing 229and extending axially from the cavity block 175. As shown in FIG. 6, thecylindrical head 217 includes a lip 233 (broadly “projection”) formingthe outer radial edge of the axial surface 209 of the knockout 205. Thehead 217 has spaced apart axial openings 237 spaced radially inward fromthe lip 233. The lip 233 facilitates clamping of the annular cutout 5between the upper tool assembly 61 and lower tool assembly 63 duringoperation of the forming tool 15. The axial openings 237 createlow-pressure cavities on the axial surface 209 of the knockout 205 thatgrip the annular cutout 5 by receiving portions of the annular cutoutand prevent the cutout from sliding during formation of the cooking ring1. The axial openings 237 in the knockout 205 can be otherwise shapedand/or omitted without departing from the scope of this invention.

A base plate 241 is attached to the lower axial surface 191 of thecavity block 175 and has an axial opening 245 that receives the guidebushing 229 and shaft 225 of the knockout 205. An insulator sheet 249 isattached to an axial end surface 251 of the base plate 241 and a heater257 extends from an external radial surface 261 of the base plate forheating the lower tool assembly 63. A fitting 263 is attached to thecylindrical shaft 225 of the knockout 205 by a threaded connectionbetween an upper portion 267 of the fitting and an inner surface 271 ofan axial recess 275 in the lower end of the shaft. In the illustratedembodiment, a bolt 281 is threadably attached to a lower end of thefitting 263. When the lower tool assembly 63 is assembled for operation,the bolt 281 is removed and an actuator (e.g., air cylinder, not shown)is optionally attached to the fitting 263 to provide an actuating forceto knockout 205. Alternatively, the lower tool assembly 63 could befixedly mounted to a support (not shown) and the upper tool assembly 61could be connected to an actuator for movement relative to the lowertool assembly.

The lower tool assembly 63 includes a blank support plate 293 supportedon the base plate 241 by a table spacer 297 (FIG. 9). The blank supportplate 293 is positioned so that an upper surface 301 of the platesupports the annular cutout 5 prior to the cutout being positioned onthe upper axial surface 187 and above the upper recess 179 of the cavityblock 175. The lower tool assembly 63 has two blank guides 305, 307attached to opposite sides of the support plate 293. The blank guides305, 307 (FIG. 10) each extend upward from the cavity block 175 and thesupport plate 293 so as to guide the annular cutout 5 into positionbetween the upper and lower tool assemblies 61, 63 of the forming tool15.

A method of forming the cooking ring 1 from annular cutout 5 isdescribed below. The cooking ring 1 of the present invention is formedfrom the annular cutout 5 by feeding the cutout into the forming toolassembly 15 and operating the assembly to press and shape the cutoutinto the forming ring. FIGS. 11A-11C show the fully open, partiallyclosed, and fully closed positions of the upper and lower toolassemblies 61, 63 and corresponding progression of the formation of thecooking ring 1 from the annular cutout 5. The forming tool assembly 15is positioned downstream from a cutting die (not shown) that cuts theannular cutout 5 from a blank of material such as paperboard havingmicrowave interactive material 9 attached thereto. The annular cutout 5can be moistened to facilitate forming of the cooking ring 1. After theupper tool assembly 61 and lower tool assembly 63 have been separatedfrom the position shown in FIG. 6, the annular cutout 5 is slid acrossthe blank support plate 293 with its radial outer portion supported bythe upper axial surface 187 of the cavity block 175 and its radial innerportion positioned above the upper recess 179 of the lower tool assembly63. The annular cutout 5 is guided to the proper position on the lowertool assembly 63 by the blank guides 305, 307 attached to the sides ofthe blank support plate 293. A conveying mechanism, such as a conveyorbelt or other suitable material handling mechanism, conveys the cutoutto the proper position between the upper tool assembly 61 and lower toolassembly 63. At the fully open position of the upper and lower toolassemblies 61, 63 (FIG. 11A), the cutout 5 is supported by the axial endsurface 187 of the cavity block 175 and the lip 233 of the knockout 205.As shown in FIG. 11A, the knockout 205 has been raised relative to thecavity block 175 so that the top surface of the lip 233 is approximatelylevel with the axial end surface 187 of the cavity block.

After the cutout 5 is positioned above the upper recess 179 of thecavity block, the upper tool assembly 61 is actuated to initiatedownward movement of the nose 67 and punch 109. As shown in FIG. 11B,the cutout 5 is initially pressed between the nose 67 and knockout 205and engages the lip 233 so that the cutout is forced into the annulargroove 77 of the nose 67. At this stage, the interference of the radialinner portion of the annular cutout 5 received in the annular groove 77and the spacing between the annular groove and the lip 233 cause theannular cutout to be gripped and clamped between the upper and lowerassemblies 63, 63 to prevent sliding of the cutout during formation ofthe cooking ring 1. As shown in FIG. 11C, the radial inner portion ofthe annular cutout 5 is gripped by the lip 233 and the groove 77 so thatthe inner radial edge 21 of the cutout stays in a fixed position as thecutting ring 1 is formed. The radial inner portion of the cutout 5(generally corresponding to the upper edge portion 45 of the cookingelement 1) stays substantially fixed as the radial outer portion of thecutout (generally corresponding to the first curved portion 37, secondcurved portion 41, and the lower edge portion 35 of the cooking element1) is pressed by the nose 67 and punch 109 against the upper recess 179of the cavity block 175 to complete the formation of the cooking ring 1.

The clamping feature of the lip 233 and groove 77 allows the formingtool assembly 15 to form a three-dimensional article from a blank 5having a precut hole. The clamping feature holds the inner radial edge21 of the blank 5 at a fixed location during formation of the blank intothe cooking ring 1 having a three-dimensional shape. This clampingfeature of the lip 233 and the groove 77 forms the annular groove 47 inthe cooking ring 1 and effectively holds the blank to control the X andY positioning of the annular cutout 5 as it moves during formation intothe shape of the cooking ring 1. It also prevents the punch from pushingthrough hole 25 in the annular blank 5. Without the use of the clampingfeature, a secondary cutting operation typically would be required toform the hole 25 in the three-dimensional article after the article isformed from the annular blank. Such an additional operation isundesirable since it would add costs and may reduce the quality of thearticle.

In addition to the capability of forming articles with a precut centerhole in the paperboard blank, the X and Y position control of the blankduring forming is beneficial to the forming of any three-dimensionalarticle or container either with or without a center hole in the blank.For example, the forming tool 15 could form a container being otherwiseshaped (e.g., round, oval, square, rectangular, etc.) from anappropriately sized and shaped blank. In one embodiment, the containercould be a three dimensional container such as a tray having a bottomwall and at least one side wall.

As shown in FIG. 11A, the lip 233 may have a height H1 ranging fromapproximately 0.01 inches (0.25 mm) to approximately 0.05 inches (1.3mm), more preferably about 0.03 inches (0.76 mm), and a radial length R1from its inner radius to its outer radius of ranging from approximately0.01 inches (0.25 mm) to approximately 0.05 inches (1.3 mm), morepreferably about 0.03 inches (0.76 mm). The annular groove 77 may have aheight H2 ranging from approximately 0.05 (1.3 mm) to approximately 0.11inches (2.8 mm), more preferably about 0.08 inches (2.0 mm), and aradial length R2 ranging from approximately 0.05 inches (1.3 mm) toapproximately 0.11 inches (2.8 mm), more preferably about 0.08 inches(2.0 mm). The foregoing dimension are illustrative of exemplarydimensions for the lip 233 and annular groove 77 that correspond to anannular blank 5 that is a laminated structure having a thickness ofapproximately 0.018 inches (0.46 mm). The present invention could beotherwise shaped and dimensioned to accommodate an annular blank havinga thickness greater than or less than the 0.018 (0.46 mm) inches withoutdeparting from the scope of this invention. The dimensional informationpresented herein is intended to be illustrative of exemplary embodimentsof the invention and is not intended to limit the scope of theinvention.

The clamp ring 135 can be actuated simultaneously with actuation of theupper and/or lower tool assemblies 61, 63 by operating the actuatorsattached to the clamp ring brackets 153, 155 to apply compression forceagainst the radial outer portion of the annular cutout 5 duringformation of the cooking ring 1. The compression force applied by theclamp ring 135 creates uniform bunching of the score lines 27 as thescore lines are formed into the pleats 49 during formation of thecooking ring 1. The compression force applied by the clamp ring 135prevents excessive bunching of the annular cutout material. The formingtool assembly 15 forms the pleats 49 of the cooking ring 1 such that thepleats have a generally U-shaped cross-sectional shape rather than aZ-shaped cross-sectional shape which would result from excessivebunching and possibly fracturing, tearing, or weakening of thepaperboard material and/or the microwave interactive material.

After the cooking ring 1 is shaped, the upper tool assembly 61 is raisedand the cooking ring is ejected from the cavity block 175 of the lowerassembly 63. The cooking ring 1 is then transported downstream of theforming tool assembly 15 by a conveying mechanism (e.g., conveyor belt)for packaging and/or shipment or for assembly into a finished foodproduct package.

The upper tool assembly 61 and lower tool assembly 63 are commonlymounted at approximately a 45° angle in a machine (not shown) of thetype manufactured by Peerless Machine & Tool Corporation in Marion,Ind., USA. The machine provides the primary compressive forces tosufficiently close and open the tool assemblies 61 and 63 of the presentinvention. The closing and opening of the tool assemblies 61, 63 by themachine forms the three-dimensional articles or containers such ascooking ring 1. In other types of machines, the tool assemblies 61, 63may include minor revisions or modifications to permit the toolassemblies to operate in alternative orientations (e.g., upside down oron their side). It should be understood that the operating position oftool assemblies 61 and 63 shown and/or described herein is not intendedto limit the scope of the invention.

As mentioned above, in accordance with the exemplary embodiment of thepresent invention, the microwave interactive material 9 may comprise amicrowave interactive element such as a susceptor. Susceptors arediscussed in greater detail below. Alternatively, the microwaveinteractive material 9 can comprise any other type of microwaveinteractive elements, materials, and/or various combinations ofmicrowave interactive elements and material, as discussed in greaterdetail below. The microwave interactive elements and materials may beomitted from article 1 without departing from the scope of thisinvention.

For example, the microwave interactive material 9 may be formed at leastpartially from one or more microwave energy interactive elements(hereinafter sometimes referred to as “microwave interactive elements”)that may promote browning and/or crisping of a particular area of thefood item, shield a particular area of the food item from microwaveenergy to prevent overcooking thereof, or transmit microwave energytowards or away from a particular area of the food item. Each microwaveinteractive element comprises one or more microwave energy interactivematerials or segments arranged in a particular configuration to absorbmicrowave energy, transmit microwave energy, reflect microwave energy,or direct microwave energy, as needed or desired for a particularconstruct and food item.

The microwave interactive element may be supported on a microwaveinactive or transparent substrate for ease of handling and/or to preventcontact between the microwave interactive material and the food item. Asa matter of convenience and not limitation, and although it isunderstood that a microwave interactive element supported on a microwavetransparent substrate includes both microwave interactive and microwaveinactive elements or components, such constructs are referred to hereinas “microwave interactive webs”.

The microwave energy interactive material may be an electroconductive orsemiconductive material, for example, a metal or a metal alloy providedas a metal foil; a vacuum deposited metal or metal alloy; or a metallicink, an organic ink, an inorganic ink, a metallic paste, an organicpaste, an inorganic paste, or any combination thereof. Examples ofmetals and metal alloys that may be suitable for use with the presentinvention include, but are not limited to, aluminum, chromium, copper,inconel alloys (nickel-chromium-molybdenum alloy with niobium), iron,magnesium, nickel, stainless steel, tin, titanium, tungsten, and anycombination or alloy thereof.

Alternatively, the microwave energy interactive material may comprise ametal oxide.

Examples of metal oxides that may be suitable for use with the presentinvention include, but are not limited to, oxides of aluminum, iron, andtin, used in conjunction with an electrically conductive material whereneeded. Another example of a metal oxide that may be suitable for usewith the present invention is indium tin oxide (ITO). ITO can be used asa microwave energy interactive material to provide a heating effect, ashielding effect, a browning and/or crisping effect, or a combinationthereof. For example, to form a susceptor, ITO may be sputtered onto aclear polymeric film. The sputtering process typically occurs at a lowertemperature than the evaporative deposition process used for metaldeposition. ITO has a more uniform crystal structure and, therefore, isclear at most coating thicknesses. Additionally, ITO can be used foreither heating or field management effects. ITO also may have fewerdefects than metals, thereby making thick coatings of ITO more suitablefor field management than thick coatings of metals, such as aluminum.

Alternatively, the microwave energy interactive material may comprise asuitable electroconductive, semiconductive, or non-conductive artificialdielectric or ferroelectric. Artificial dielectrics comprise conductive,subdivided material in a polymeric or other suitable matrix or binder,and may include flakes of an electroconductive metal, for example,aluminum.

In one example, the microwave interactive element may comprise a thinlayer of microwave interactive material (generally less than about 100angstroms in thickness, for example, from about 60 to about 100angstroms in thickness) that tends to absorb at least a portion ofimpinging microwave energy and convert it to thermal energy (i.e., heat)at the interface with a food item. Such elements often are used topromote browning and/or crisping of the surface of a food item(sometimes referred to as a “browning and/or crisping element”). Whensupported on a film or other substrate, such an element may be referredto as a “susceptor film” or, simply, “susceptor”. However, othermicrowave energy interactive elements, such as those described herein,are contemplated hereby.

As another example, the microwave interactive element may comprise afoil having a thickness sufficient to shield one or more selectedportions of the food item from microwave energy (sometimes referred toas a “shielding element”). Such shielding elements may be used where thefood item is prone to scorching or drying out during heating.

The shielding element may be formed from various materials and may havevarious configurations, depending on the particular application forwhich the shielding element is used. Typically, the shielding element isformed from a conductive, reflective metal or metal alloy, for example,aluminum, copper, or stainless steel. The shielding element generallymay have a thickness of from about 0.000285 inches to about 0.05 inches.In one aspect, the shielding element has a thickness of from about0.0003 inches to about 0.03 inches. In another aspect, the shieldingelement has a thickness of from about 0.00035 inches to about 0.020inches, for example, 0.016 inches.

As still another example, the microwave interactive element may comprisea segmented foil or high optical density evaporated material(collectively referred to as “segmented foil”), such as, but not limitedto, those described in U.S. Pat. Nos. 6,204,492, 6,433,322, 6,552,315,and 6,677,563, each of which is incorporated by reference in itsentirety. Although segmented foils are not continuous, appropriatelyspaced groupings of such segments often act as a transmitting element todirect microwave energy to specific areas of the food item. Such foilsalso may be used in combination with browning and/or crisping elements,for example, susceptors.

Any of the numerous microwave interactive elements described herein orcontemplated hereby may be substantially continuous, that is, withoutsubstantial breaks or interruptions, or may be discontinuous, forexample, by including one or more breaks or apertures that transmitmicrowave energy therethrough. The breaks or apertures may be sized andpositioned to heat particular areas of the food item selectively. Thenumber, shape, size, and positioning of such breaks or apertures mayvary for a particular application depending on type of construct beingformed, the food item to be heated therein or thereon, the desireddegree of shielding, browning, and/or crisping, whether direct exposureto microwave energy is needed or desired to attain uniform heating ofthe food item, the need for regulating the change in temperature of thefood item through direct heating, and whether and to what extent thereis a need for venting.

It will be understood that the aperture may be a physical aperture orvoid in the material used to form the construct, or may be anon-physical “aperture”. A non-physical aperture may be a portion of theconstruct that is microwave energy inactive by deactivation orotherwise, or one that is otherwise transparent to microwave energy.Thus, for example, the aperture may be a portion of the construct formedwithout a microwave energy active material or, alternatively, may be aportion of the construct formed with a microwave energy active materialthat has been deactivated. While both physical and non-physicalapertures allow the food item to be heated directly by the microwaveenergy, a physical aperture also provides a venting function to allowsteam or other vapors to be released from the food item.

In some instances, it may be beneficial to create one or morediscontinuities or inactive regions to prevent overheating or charringof the construct and/or food product, for example, by forming areas ofthe blank without a microwave energy interactive material, removing themicrowave energy interactive material that has been applied, or bydeactivating the microwave energy interactive material in these areas.Further still, one or more panels, portions of panels, or portions ofthe construct may be designed to be microwave energy inactive to ensurethat the microwave energy is focused efficiently on the areas to bebrowned and/or crisped, rather than being lost to portions of the fooditem not intended to be browned and/or crisped or to the heatingenvironment.

As stated above, any of the above elements and numerous otherscontemplated hereby may be supported on a substrate. The substratetypically comprises for example, a polymeric film or material. As usedherein the term “polymer” or “polymeric material” includes, but is notlimited to, homopolymers, copolymers, such as for example, block, graft,random, and alternating copolymers, terpolymers, etc. and blends andmodifications thereof. Furthermore, unless otherwise specificallylimited, the term “polymer” shall include all possible geometricalconfigurations of the molecule. These configurations include, but arenot limited to isotactic, syndiotactic, and random symmetries.

The thickness of the film typically may be from about 35 gauge to about10 mil. In one aspect, the thickness of the film is from about 40 toabout 80 gauge. In another aspect, the thickness of the film is fromabout 45 to about 50 gauge. In still another aspect, the thickness ofthe film is about 48 gauge. Examples of polymeric films that may besuitable include, but are not limited to, polyolefins, polyesters,polyamides, polyimides, polysulfones, polyether ketones, cellophanes, orany combination thereof. Other non-conducting substrate materials suchas paper and paper laminates, metal oxides, silicates, cellulosics, orany combination thereof, also may be used.

In one example, the polymeric film comprises polyethylene terephthalate(PET). Polyethylene terephthalate films are used in commerciallyavailable susceptors, for example, the QWIKWAVE® susceptor and theMICRORITE® susceptor laminations, both available from Graphic PackagingInternational (Marietta, Ga.). Examples of polyethylene terephthalatefilms that may be suitable for use as the substrate include, but are notlimited to, MELINEX®, commercially available from DuPont Teijan Films(Hopewell, Va.), SKYROL, commercially available from SKC, Inc.(Covington, Ga.), and BARRIALOX PET, available from Toray Films (FrontRoyal, Va.), and QU50 High Barrier Coated PET, available from TorayFilms (Front Royal, Va.).

The polymeric film may be selected to impart various properties to thepaper or paperboard web, for example, printability, heat resistance, orany other property. As one particular example, the polymeric film may beselected to provide a water barrier, oxygen barrier, or a combinationthereof. Such barrier film layers may be formed from a polymer filmhaving barrier properties or from any other barrier layer or coating asdesired. Suitable polymer films may include, but are not limited to,ethylene vinyl alcohol, barrier nylon, polyvinylidene chloride, barrierfluoropolymer, nylon 6, nylon 6,6, coextruded nylon 6/EVOH/nylon 6,silicon oxide coated film, barrier polyethylene terephthalate, or anycombination thereof.

One example of a barrier film that may be suitable for use with thepresent invention is CAPRAN® EMBLEM 1200M nylon 6, commerciallyavailable from Honeywell International (Pottsville, Pa.). Anotherexample of a barrier film that may be suitable is CAPRAN® OXYSHIELD OBSmonoaxially oriented coextruded nylon 6/ethylene vinyl alcohol(EVOH)/nylon 6, also commercially available from HoneywellInternational. Yet another example of a barrier film that may besuitable for use with the present invention is DARTEK® N-201 nylon 6,6,commercially available from Enhance Packaging Technologies (Webster,N.Y.). Additional examples include BARRIALOX PET, available from TorayFilms (Front Royal, Va.) and QU50 High Barrier Coated PET, availablefrom Toray Films (Front Royal, Va.), referred to above.

Still other barrier films include silicon oxide coated films, such asthose available from Sheldahl Films (Northfield, Minn.). Thus, in oneexample, a susceptor may have a structure including a film, for example,polyethylene terephthalate, with a layer of silicon oxide coated ontothe film, and ITO or other material deposited over the silicon oxide. Ifneeded or desired, additional layers or coatings may be provided toshield the individual layers from damage during processing.

The barrier film may have an oxygen transmission rate (OTR) as measuredusing ASTM D3985 of less than about 20 cc/m2/day. In one aspect, thebarrier film has an OTR of less than about 10 cc/m2/day. In anotheraspect, the barrier film has an OTR of less than about 1 cc/m2/day. Instill another aspect, the barrier film has an OTR of less than about 0.5cc/m2/day. In yet another aspect, the barrier film has an OTR of lessthan about 0.1 cc/m2/day.

The barrier film may have a water vapor transmission rate (WVTR) of lessthan about 100 g/m2/day as measured using ASTM F1249. In one aspect, thebarrier film has WVTR of less than about 50 g/m2/day. In another aspect,the barrier film has a WVTR of less than about 15 g/m2/day. In yetanother aspect, the barrier film has a WVTR of less than about 1g/m2/day. In still another aspect, the barrier film has a WVTR of lessthan about 0.1 g/m2/day. In a still further aspect, the barrier film hasa WVTR of less than about 0.05 g/m2/day.

Other non-conducting substrate materials such as metal oxides,silicates, cellulosics, or any combination thereof, also may be used inaccordance with the present invention.

The microwave energy interactive material may be applied to thesubstrate in any suitable manner, and in some instances, the microwaveenergy interactive material is printed on, extruded onto, sputteredonto, evaporated on, or laminated to the substrate. The microwave energyinteractive material may be applied to the substrate in any pattern, andusing any technique, to achieve the desired heating effect of the fooditem.

For example, the microwave energy interactive material may be providedas a continuous or discontinuous layer or coating including circles,loops, hexagons, islands, squares, rectangles, octagons, and so forth.Examples of various patterns and methods that may be suitable for usewith the present invention are provided in U.S. Pat. Nos. 6,765,182;6,717,121; 6,677,563; 6,552,315; 6,455,827; 6,433,322; 6,414,290;6,251,451; 6,204,492; 6,150,646; 6,114,679; 5,800,724; 5,759,422;5,672,407; 5,628,921; 5,519,195; 5,424,517; 5,410,135; 5,354,973;5,340,436; 5,266,386; 5,260,537; 5,221,419; 5,213,902; 5,117,078;5,039,364; 4,963,424; 4,936,935; 4,890,439; 4,775,771; 4,865,921; andRe. 34,683, each of which is incorporated by reference herein in itsentirety. Although particular examples of patterns of microwave energyinteractive material are shown and described herein, it should beunderstood that other patterns of microwave energy interactive materialare contemplated by the present invention.

The microwave interactive element or microwave interactive web may bejoined to or overlie a dimensionally stable, microwave energytransparent support (hereinafter referred to as “microwave transparentsupport”, “microwave inactive support” or “support”) to form theconstruct.

In one aspect, for example, where a rigid or semi-rigid construct is tobe formed, all or a portion of the support may be formed at leastpartially from a paperboard material, which may be cut into a blankprior to use in the construct. For example, the support may be formedfrom paperboard having a basis weight of from about 60 to about 330lbs/ream, for example, from about 80 to about 140 lbs/ream. Thepaperboard generally may have a thickness of from about 6 to about 30mils, for example, from about 12 to about 28 mils. In one particularexample, the paperboard has a thickness of about 18 mils and a basisweight of from about 100 lbs/ream to about 300 lbs/ream. Any suitablepaperboard may be used, for example, a solid bleached or solidunbleached sulfate board, such as SUS® board, commercially availablefrom Graphic Packaging International.

In another aspect, where a more flexible construct is to be formed, thesupport may comprise a paper or paper-based material generally having abasis weight of from about 15 to about 60 lbs/ream, for example, fromabout 20 to about 40 lbs/ream. In one particular example, the paper hasa basis weight of about 25 lbs/ream.

Optionally, one or more portions of the various blanks or otherconstructs described herein or contemplated hereby may be coated withvarnish, clay, or other materials, either alone or in combination. Thecoating may then be printed over with product advertising or otherinformation or images. The blanks or other constructs also may be coatedto protect any information printed thereon.

Furthermore, the blanks or other constructs may be coated with, forexample, a moisture and/or oxygen barrier layer, on either or bothsides, such as those described above. Any suitable moisture and/oroxygen barrier material may be used in accordance with the presentinvention. Examples of materials that may be suitable include, but arenot limited to, polyvinylidene chloride, ethylene vinyl alcohol, DuPontDARTEK™ nylon 6,6, and others referred to above.

Alternatively or additionally, any of the blanks or other constructs ofthe present invention may be coated or laminated with other materials toimpart other properties, such as absorbency, repellency, opacity, color,printability, stiffness, or cushioning. For example, absorbentsusceptors are described in U.S. Provisional Application No. 60/604,637,filed Aug. 25, 2004, and U.S. Patent Application Publication No.2006/0049190, published Mar. 9, 2006, both of which are incorporatedherein by reference in their entirety. Additionally, the blanks or otherconstructs may include graphics or indicia printed thereon.

It will be understood that with some combinations of elements andmaterials, the microwave interactive element may have a grey or silvercolor this is visually distinguishable from the substrate or thesupport. However, in some instances, it may be desirable to provide aweb or construct having a uniform color and/or appearance. Such a web orconstruct may be more aesthetically pleasing to a consumer, particularlywhen the consumer is accustomed to packages or containers having certainvisual attributes, for example, a solid color, a particular pattern, andso on. Thus, for example, the present invention contemplates using asilver or grey toned adhesive to join the microwave interactive elementsto the substrate, using a silver or grey toned substrate to mask thepresence of the silver or grey toned microwave interactive element,using a dark toned substrate, for example, a black toned substrate, toconceal the presence of the silver or grey toned microwave interactiveelement, overprinting the metallized side of the web with a silver orgrey toned ink to obscure the color variation, printing thenon-metallized side of the web with a silver or grey ink or otherconcealing color in a suitable pattern or as a solid color layer to maskor conceal the presence of the microwave interactive element, or anyother suitable technique or combination thereof.

As another example, the microwave interactive material 9 includes one ormore susceptors as well as closed cells formed between layers ofpackaging material. Upon exposure to microwave energy, the cells expandto form inflated cells that thermally insulate the food item in thepackage from the environment exterior to the package. In addition, theinflated cells can force one or more susceptors into contact with, or atleast closer to, the food being heated, cooked, or the like. One exampleof a microwave packaging material that provides inflatable cells isdescribed in PCT application PCT/US03/03779 titled “Insulating MicrowaveInteractive Packaging”, the entire disclosure of which is herebyincorporated by reference herein.

The foregoing description of the invention illustrates and describesvarious embodiments of the present invention. As various changes couldbe made in the above construction without departing from the scope ofthe invention, it is intended that all matter contained in the abovedescription or shown in the accompanying drawings shall be interpretedas illustrative and not in a limiting sense. Furthermore, the scope ofthe present invention covers various modifications, combinations, andalterations, etc., of the above-described embodiments that are withinthe scope of the claims. Additionally, the disclosure shows anddescribes only selected embodiments of the invention, but the inventionis capable of use in various other combinations, modifications, andenvironments and is capable of changes or modifications within the scopeof the inventive concept as expressed herein, commensurate with theabove teachings, and/or within the skill or knowledge of the relevantart. Furthermore, certain features and characteristics of eachembodiment may be selectively interchanged and applied to otherillustrated and non-illustrated embodiments of the invention withoutdeparting from the scope of the invention.

1. A tool for forming a cooking element from an annular cutout having aninner edge and an outer edge, the tool comprising: a first toolassembly; and a second tool assembly, at least one of the first toolassembly and the second tool assembly being moveable between an openposition wherein the annular cutout is received between the first andthe second tool assembly and a closed position wherein the cutout isformed into the cooking element, the first and the second tool assemblyhaving a cooperating clamping feature that holds a portion of theannular cutout comprising the inner edge in a fixed position duringformation of cooking element.
 2. The tool of claim 1 wherein the firsttool assembly comprises a nose having an external surface shaped togenerally correspond to at least a portion of the cooking element andthe second tool assembly comprises a cavity block having a recess shapedto correspond with at least a portion of the cooking ring, the nose andthe cavity block cooperating to form the cooking element from theannular cutout when the nose is at least partially received in thecavity block.
 3. The tool of claim 2 wherein the second tool assemblyhas a knockout slidingly received in the cavity block and axiallymoveable with respect to the cavity block, the knockout is forcooperating with the cavity block and the nose to form the cookingelement from the annular cutout.
 4. The tool of claim 3 wherein thecooperating clamping feature comprises a groove on the external surfaceof the nose and a lip on an external surface of the knockout, the lipprojecting from the external surface of the knockout and is at leastpartially received in the groove at the closed position of the first andsecond tool assemblies.
 5. The tool of claim 4 wherein the recess of thecavity block is formed by a curved external surface of the cavity blockthat generally corresponds to the shape of the cooking element.
 6. Thetool of claim 5 wherein the external surface of the knockout and theexternal surface of the nose cooperate to initially grip a radiallyinner portion of the annular cutout prior to positioning the first andsecond tool assemblies in the closed position.
 7. The tool of claim 6wherein the knockout has a plurality of axial openings for creating lowpressure cavities on the external surface of the knockout to enhance theinitial gripping of the cutout.
 8. The tool of claim 5 wherein thecurved external surface of the cavity block comprises a first curvedsurface and a second curved surface, the first and second curvedsurfaces respectively correspond to first and second curved portions ofthe cooking element.
 9. The tool of claim 4 wherein the first toolassembly includes a punch operatively connected to the nose, the punchhas an external surface that cooperates with an external surface of thenose to form a forming surface of the upper tool assembly that generallycorresponds to the shape of the cooking element.
 10. The tool of claim 9wherein the upper tool assembly includes a recess in the punch and aspring received in the recess, the spring being for applying a forceagainst the nose to provide spacing between the nose and the punchduring formation of the cooking element.
 11. The tool of claim 4 whereinthe external surface of the knockout is an axial surface, and the lipcomprises an outer radial edge of the axial surface.
 12. A method offorming a cooking element from an annular cutout having an inner edgeand an outer edge, the method comprising: providing a tool comprising afirst tool assembly and a second tool assembly, the first and secondtool assemblies having a cooperating clamping feature, providing aannular cutout comprising material to be formed into the cookingelement; clamping the annular cutout between the clamping feature of thefirst tool assembly and the second tool assembly; positioning the firstand second tool assemblies in a closed position to press the cutoutbetween the tool assemblies and form the cutout into the cooking elementwhile maintaining a portion of the annular cutout comprising the inneredge in a substantially fixed position.
 13. The method of claim 12wherein the first tool assembly comprises a nose having an externalsurface shaped to generally correspond to at least a portion of thecooking element and the second tool assembly comprises a cavity blockhaving a recess, the positioning the first and second tool assembliescomprises pressing the annular cutout between the nose and the cavityblock to form the annular cutout into the cooking element.
 14. Themethod of claim 13 wherein the second tool assembly comprises a knockoutaxially moveable with respect to the cavity block and having a lipprojecting from an external surface of the knockout, the first toolassembly comprises a groove on the external surface of the nose, theclamping the annular cutout comprises contacting the cutout with theexternal surface of the nose and the lip and forcing the lip and aportion of the annular cutout into the groove.
 15. The method of claim14 wherein the clamping the annular cutout comprises downwardly movingthe nose to force the portion of the annular cutout into the grove andthe positioning the first and second tool assemblies comprises furtherdownwardly moving the nose to force the annular cutout into the recessand form the annular cutout into the cooking element.
 16. The method ofclaim 14 wherein the external surface of the knockout is an axialsurface, and the lip comprises an outer radial edge of the axialsurface.
 17. A cooking element formed by the method of claim
 12. 18. Thecooking element of claim 17 wherein the cooking element has a flat upperedge portion, a flat lower edge portion, and at least one curved portionbetween the upper and lower edge portion.
 19. The cooking element ofclaim 18 wherein the cooking element comprises a microwave interactivematerial.
 20. A method of forming a cooking element, the methodcomprising: providing a tool comprising a first tool assembly and asecond tool assembly; cutting an annular cutout from a blank, theannular cutout having an outer radial edge, an inner radial edge, and anopening adjacent the inner radial edge; positioning the tool in an openposition wherein the first tool assembly and the second tool assemblyare spaced apart to form a receiving space therebetween; conveying theannular cutout to the tool in the open position and placing the cutoutbetween the first and second tool assembly; closing the tool so that thefirst and second tool assemblies form the annular cutout into a cookingring.
 21. The method of claim 20 wherein the first tool assemblycomprises a nose having an external surface shaped to generallycorrespond to at least a portion of the cooking element and the secondtool assembly comprises a cavity block having a recess, the closing thetool comprises pressing the cutout between the nose and the cavity blockto shape the annular cutout into the cooking element.
 22. The method ofclaim 21 wherein the second tool assembly comprises a knockout axiallymoveable with respect to the cavity block, the closing the toolcomprises initially gripping a portion of the annular cutout between thenose and the knockout prior to shaping the annular cutout into thecooking element.
 23. The method of claim 21 wherein an inner radial edgeportion of the annular cutout is initially gripped between the nose andthe knockout.
 24. The method of claim 21 wherein the first tool assemblycomprises a groove on the external surface of the nose and a lipprojecting from an external surface of the knockout, the initiallygripping the portion of the annular cutout comprises contacting theannular cutout with the external surface of the nose and the lip toforce the lip and a portion of the cutout into the groove.
 25. Themethod of claim 24 wherein the external surface of the knockout is anaxial surface, and the lip comprises an outer radial edge of the axialsurface.
 26. The method of claim 21 wherein the initially gripping theportion of the annular cutout comprises downwardly moving the nose andthe closing the tool comprises further downward movement of the nose toeffect downward movement of the knockout during forming of the annularcutout into the cooking ring.
 27. A cooking element formed by the methodof claim 20, wherein the cooking element has a flat upper edge portion,a flat lower edge portion, and at least one curved portion between theupper and lower edge portion.
 28. The cooking element of claim 27wherein the cooking element comprises a microwave interactive material.29. A cooking element for heating a food product, the cooking elementcomprising a generally annular body comprising a lower edge portion, anupper edge portion, a curved portion between the lower and upper edgeportions, and an annular groove between the upper edge portion and thecurved portion.
 30. The cooking element of claim 29 wherein the upperedge portion and the lower edge portion are substantially flat.
 31. Thecooking element of claim 29 wherein the curved portion is a first curvedportion and the body further comprises a second curved portion.
 32. Thecooking element of claim 29 wherein the upper edge portion has an innerradial edge that at least partially defines an opening in the cookingelement.
 33. The cooking element of claim 29 wherein the body comprisesa first layer and a second layer, the first layer comprising paperboardand the second layer comprising a microwave interactive material. 34.The cooking element of claim 33 wherein the first layer is an outerlayer and the second layer is an inner layer.
 35. The cooking element ofclaim 29 wherein the body comprises pleats in the curved portion, thepleats respectively comprising overlapped material of the body that iscompressed to strengthen the cooking element.
 36. The cooking element ofclaim 29 wherein the annular groove is initially formed in the cookingelement to grasp the cooking element prior to formation of the curvedportion.